Generally, a crossed-dipole antenna includes a first dipole with a first pair of radiating elements that are in some fashion oriented in or about a first plane and a second dipole with a second pair of radiating elements that are oriented in or about a second plane that is substantially perpendicular to the first plane. The radiating elements can be any of a number of different types (e.g., wires, triangles, spades etc.). Typically, all of the radiating elements in a crossed-dipole are of the same type.
In one type of crossed-dipole antenna, a first dipole is established on a first planar dielectric substrate and a second dipole is established on a second dielectric substrate. The first and second dipoles are typically established on their respective substrates by well-known printing and/or etching techniques. In many cases, the first and second planar dielectric substrates are disposed perpendicular to one another and perpendicular to a mounting/feed substrate. The mounting/feed substrate provides a first set of connection points for electrically connecting one of the dipoles to feed circuitry that is connected to or established on the mounting/feed substrate and a second set of connection points for electrically connecting the other dipole to feed circuitry that is also connected to or established on the mounting/feed substrate.
In many instances, the mechanical connection between the first and second substrates with their respective dipoles is established using an “egg crate” technique in which an “upwardly” extending slot associated with the first substrate receives a portion of the second substrate and “downwardly” extending slot associated with the second substrate receives a portion of the first substrate. An example, of this technique is disclosed in U.S. Pat. No. 4,686,536.
While the “egg crate” technique mechanically connects the two substrates, the connection typically allows the substrates to rotate relative to one another such that the first and second substrates and their dipoles are not substantially perpendicular to one another. To establish the needed perpendicular relationship, two techniques are frequently employed. The first technique connects a brace to each of the substrates to establish the needed perpendicularity. In the second technique, a mounting/feed substrate defines holes/slots that each receive a portion of each the first and second substrates in a manner that establishes the requisite perpendicularity between the substrates. Arrays of crossed-dipole antennas in which the dipole antennas have been established on planar dielectric substrates and the needed perpendicularity established with braces and/or mounting slots have also been created.